Expansion joint



Nov. 2 6, 1929. R. E. MARTIN 1,737,318

EXPANSION JOINT Filed May 25, 1929 Patented Nov. 26, 1929 UNITED STATES PATENT OFFICE ROBERT E. MARTIN, DECEASED, LATE OF JACKSON, MISSISSIPPI; BY MADIE PARSONS MARTIN, ADMINISTBATRIX, OF JACKSON, MISSISSIPPI ExPANsIoN JOINT Application filed May 25, 1929. Serial No. 365,997. I

The present invention relates to the construction of roadways of concrete and like materials, and more particularly to the expansion joints of such roadways.

The object of the invention is to provide a convenient and eflicient joint unit of improved character, whereby the construction of the roadway is simplified and the strength and durability thereof is enhanced.

In constructing roadways or similar structures of concrete or the like, it is necessary to make provision for the expansion and contraction of the concrete under variations of temperature. Unless such provision is made, ordinary changes of temperature cause rapid breaking up and deterioration of the road surface.

Ithas been proposed heretofore to provide for the expansion and contraction of the con- 2.0 crete by forming expansion joints at intervals in the road. The joints are filled with plastic or yielding material. either poured in liquid form into thejoint or inserted therein as a preformed slab. A The joints constructed by flowing asphalt or creosote material between the sections of the roadway are laborious and expensive to make and are often unsatisfactory in char-' acter. The use of a preformed slab is a distinct improvement but even the joints'heretofore constructed in this manner have certain disadvantages.

It has been found that these disadvantages may be overcome-and a joint of improved 5 character may be constructed in accordance with the present invention which contemplates an expansion joint embodying a pre formed slab or block formed by heating and compressing mechanically disintegrated or 4-0 exploded wood fibres, the slab being impregnated with asphaltic or creosote material. In general. the impregnating material may be any yielding, water-proofing substance that may be incorporated in the slab or base by an 5 impregnating process. The fibrous base preferably consists of a material commonly known as masonite or masonite fibre. and particular- 1y that'variety of masonite having a hard surface portion and a relatively soft core.

In the accompanying drawings, Fig. 1 is a sectional view of a portion of a roadway embodying the invention, and

Fig. 2 is a perspective view of the preformed slab employed in constructing the expansion joint shown in. Fig. 1.

Referring to the drawings, a portion of a roadway is shown in Fig. 1 embodying sections 1 and 2 of concrete or similar material having an expansion joint 3 interposed therebetween.

As shown in Fig. 2. the expansion joint 3 comprises a preformed slab or block of compressed fibrous material, such for example as is known to the trade as masonite or masonite fibre. The preformed slab or block is impregnated with asphaltic or creosote material or the like. Satisfactory results have beenobtained with 50-60 penetration asphalt. heated to approximately 450 F.. the slab being immersed in the heated bath for 25 or 30 minutes. The process is preferably carried out in such a manner as to insure complete saturation of pressure of about 250 to 1000 lbs. per sq. in.

In a process of this kind, the lignins are retained whereas in processes involving chemical digestion, the lignins are removed or al tered in character. Apparently the lignins, under the subsequent steps of the process. serve to produce a binding or coherin'g of the cellulose. fibres whereby the fibrous strip when impregnated, has those characteristics which are desired in an expansion joint.

After being fibrated. the woody material is formed into a felted sheet in the usual manner and this sheet is compressed for a sufficient period of time and at such a temperature and pressure as to produce a strong slab of the desired characteristics. While the pressures and temperatures may be varied, it

has been found that low pressures produce a slab having a soft core which is particularly advantageous, although relatively high pressures may be employed in some instances. Suitable processes for making masonite fibre are well known in the art, and form the subject-matter of prior patents, such as Nos. 1,663,504 and 1,663,505 granted to W. 11. Mason on March 20, 1928.

It has been found that a fibrous slab formed in this manner and impregnated with asphalt or the like is especially adapted for use as an expansion joint of a roadway. The

slabs may be cut to the desired size and shipped in quantity .to the point of construction and the impregnation of the slabs may be effected when the joints are constructed during the building of the roadway.

What is claimed is: 1. An expansion joint for concrete paving 'and the like comprising a slab of mechanically disintegrated and compressed wood fibers containing substantially all the constituents of the original raw material, said slabbeing impregnated with a yielding, water-proofing material.

' 2. An expansion joint for concrete paving and the like comprising a slab of mechan ically disintegrated and compressed wood fibres containing substantially all the constit: uents of the original raw material, said slab being impregnated with asphaltic material.

3. An expansion joint for concrete paving and the like comprising a slab formed from exploded and compressed fibrous material and impregnated with asphaltic material.

4. An expansion joint for concrete paving and the like comprising a slab of mechanically disintegrated and compressed wood fibres containing substantially all the ,constituents of the original raw material, said slab having asphalt incorporated therein.

5. The method of constructing an expanv sion joint comprising the step of impregnating with asphaltic material a slab of exploded fibrous material, the asphaltic material hewoody material which has been compressed until the surface is relatively 'dense'and hard and the core is of lesser density and hardness. 6. The method of constructing an expansion joint comprising the step of impregnating by immersion in asphaltic material of -60 ,penetration for substantially one-half hour a slab of exploded and compressed ing maintained at a temperature of, substantially 450 F. MADIE PARSONS MARTIN,

Administratfim. 

